Contra-angle dental handpiece



April 2, 1940. H. H. BEARDSLEY' CONTRA-ANGLE DENTAL HANDPIEGE 2Sheets-Sheet 1 Filed April 27, 1937 1 Magi April 2, 1940.

H. H. BEARDSLEY CONTRA-ANGLE DENTALv HANDPIECE 2 Sheets-Sheet 2rrr/67431441514.

Filed April 27 1937 l l BY PER

Patented Apr. 2, 1940 UNITED stares l rarest orrics 2,195,555k l f u i.y

u CONTRA-ANGLE DENTAL HANDPIEVCE Harold H.' lvearilsley, Denver, Colo."Application April v2&7, 1937, seriai No. 139,152

9 clams.` (ci. 52m-2n' This invention relates to improvement indentalcontra-angle hand pieces and particularly mission of the burr shankythereinto and for clamping the burr shank in operative position., and(d) providinga rotating clamping means vhaving a smoothexterior. v

' With'these` and other objects in View, as willy hereinafter more fullyappear, my invention comprises certain novell constructions,combinations and arrangements of parts as described in the followingspecification and dened in the appendedclaims and illustrated in theaccompanying drawings in which:

Fig. 1 is a side elevation of a complete contra-angle hand piecerconstructed according to my invention. A l

Fig. 2 vis an enlarged fragment of Fig. 1. partly in elevation butmostly in vcentral section illustrating the contracting sleeve inclamping position.A

Fig. 3 is a sectional View on line 3--3 of Fig.'2 looking in thedirection of the arrows but not includingthe burr and showing thelcontracting sleeve in released position.

Fig. 4 is an elevation showing detail chuck in Figs. 2 and 3,forftapered burr shank.

Fig. 5 is a section on line 5-5 .of Fign4 looking in the direction ofthe arrows.

Fig. 6 isa detail view of a burr with parallel` sided shank.

- Fig. 'Tis a longitudinal section ofa modified closed Atherein as nowin common use, suchA handle, including the enclosed parts, beinggenerally indicated at H. Such a handle carries a tubular member Iwhich, in turn, carries head housing 2, here illustrated 'as integralwith the tubular member l. Within member. 4I is the 55 usual operatingshaft 3 carrying suitable gear 4 ofthe which mesheswith gear 5 carriedby hub having.v shoulder 1 Vwhich bears on a suitable bearing withinhousing 2 such as' the innerend of sleeve 8 threaded intok housing 2 andprovided withl a head 9 for operation thereof andfor Alimiting itsmovement into the housing.

, Hub 6 carries an axially positioned chuck I havingan axial bore II foraccommodationof the shank` cfa burr;v The bore II and'shank I 2 of theburr are vco-mating and may be tapered as illustrated in Figs. 2 and 3.The chuck lil is `reducedas at Illa and terminates in a frustoconicalbearing IIlband is provided with a collar Ic. f

The lower or outer end of thev chuck l0 is slit as at |13 to formwspringfingers Ill and-these iingers are preferably provided with projections.

rotation'ofthe shank' with the` chuck will be insured but to insure suchrotation even in case of inaccurate construction, positive means tosecure such rotation may be provided as flat'. faced extension I1 ci theshank and stop I8on the inner wall 'of bore II so positioned Athat itwill ybe encountered by extension I'I` in case of any rotative slip ofshank I2 in bore II.,-

It wil1`be understood that shank I2 isrto be inserted in bore II `untillit fits snugly therein and projectionsll are so positioned as to engageshoulder I6 when shank I2 is thus seated and fingers I4 have beencontracted. `'Accordingly taperedy shank I2 will be snugly seated in'vtapered bore II and will be positively held againstlongitudinal movementoutwardly fromthe chucky when ngers I4 are contracted as illustrated inFig. 2.- Normally the fingersv I -if-fiare outwardly to a degree whichpermits the insertion and withdrawal -of burr shank I2 withoutobstruction by projections v,I5 so that in order to clamp the shankwithin the chuck as illustrated in Figure 2J means "'must'be providedfor pressing the fingers I4 inwardly after the shank has been insertedin the` chuck. Such means must also, y

be capable of releasing such pressure, allowing 4 ngers I4 toresumetheir normal position when For thispurpose I provide a slidablecontractingsleeve or ring I9 slidably enclosing the lower end of .chuckIll and provided at its lower end it is desired to withdraw the-shankfrom the Suitable means as bevelled shoulder 2l, are provided forcontracting lingers I4 and guiding.

the ends thereof into bore 2U Whensleeve ,I9 is forced up over the chuckI from position shown` in Fig. 3 to that shown in Fig. 2, f

22, the lever being fulcrumed at 23, in lug 24 here shown as carried bymember I and housing 2. The ends 25 of lever 22 engage sleeve I9 in anysuitable manner for permitting rotation of sleeve I9 While insuringlongitudinal movement of the sleeve I9 with ends 25 of the lever whenthe lever is moved between the solid line position shown in Figs. l and2 and the position indicated by dotted lines in Fig. 2 and shown insolid lines in Fig.v 3; Such means may consist of annular groove 26 insleeve I9 to accommodate ends 25 of the lever 22 which endsare, for thispurpose, preferably rounded as clearly shown at Fig. 1.

Bearing member 2l is threaded into housing 2, the-frusto-conical bearingIIlb being seated therein.

Normally ends 25 of the lever will retain sleeve I9 even when inunclamped position as 'shown at Fig. 3 so that inadvertent dropping ofsleeve It' is provided against and sleeve I9 is normally automaticallyretained in position for insertion and clamping of the shank and loss ofthe clamping members is prevented. Two objections toa threaded clampingmember, viz: the danger of misplacement or dropping of the member andthe knurled or roughened surface provided on such member for turning thesame, are therei fore obviated by my invention.

Furthermore the operation of my clamping and releasing structure issimplified and facilitated,

such operation being accomplished by the thumb or nger of the hand ofthe operator While holding the handpiece in usual manner.

` For burrs having parallel sided shanks as shown in Fig. 6, I provide achuck of form shown in Fig. 7 which is the samev in principle ofconstruction and operation as the chuck shown in the other figures,having the same slot I3 and spring iingers I4, with preferableprojections I5. In this modied structure, however, I provide bevelledshoulder 2.8 on the shank and bevelled seat 29 in the bore of the chuckand recess 3i) for reception of flat facedexte'nsion `3I to insurerotation of the burr with the chuck.

In Figs. 8 and 9 I have villustrated modifications of structural detailsof my means for eX- erting a resilient grip on a burr shank havingparallel sides. Withsucha shank, accurately seated in the chuck, it willbe found unnecessary to have the spring fingers contracted for- Ward ofthe shoulder of the shank, a resilient grip on the parallel sides of theshankl being suihcient. In such case vthe spring fingers I4 may beformed With outwardly projectingportions such as 32 in Fig. 8 or 33 inFig. 9. In

such case also the sleeve I9- is structurally modified so that when itis forced over the fingers I4 it will contract the projections 32 or 33,as the case may be, thus forcing those portions of the fingers which areadjacent the sides of the shank to grip the Shank in a resilient gripthus minimizing the danger of loosening of parts due to vibration. v

.The smallness of `dental hand pieces and the parts thereof and thecorresponding minuteness ofsorne of the elements should be kept in mindfor clear understanding of this specification and the accompanyingillustrative drawings. For example, projections I will perform theirfunctions'if only 1%000 or even 1A000 of an inch in depth.

Other dimensions may be correspondingly mi- For moving sleeve I9 intoorout of the clampy ing position shown in Fig. 2 I provide a leverpreferably of bell crank U form as indicated atnute.

While I have illustrated and described many detailsof vconstructionl donot wish to be restricted thereto because many changes in such details,within the spirit of my invention and the scope of the appended claims,will be obvious to those skilled in the art.

l. In a dental handpiece, in combination, a housing, a chuck rotatablymounted in the housing and adapted to receive a burr shank having ashoulder, the :shank-receiving end of the chuck being divided into aplurality of resilient 'members extendingfrom said end of said chuckinwardly beyond saidf'shoulder'when the shank is seatedin the chuck andmeans slidable over the ends' of said members fadapted to contract ysaidmembers and causesaid members to resiliently grip said shoulder and'abifurcated bell-crank lever fulcrurned on' said housing with its Weightarms engaging said slidable means for moving said slidable means intoand out of contracting engagement with said resilient members.

` 2. In a'v dental handpiece, in combination, a housing, a chuckrotatably mounted inthe 'housing and adapted to receive a burr shankhaving a shouldenftheshank-receiving end of, the chuck being dividedinto a plurality of resilient' members extending from said end of Saidchuck inwardly 'beyond said shoulder when theshank is seated inthevchuckand means slidable over the ends of said members adapted tocontract-said membersvand cause said' membersvto resiliently grip saidshoulderand a bifurcated bell-crank leverfulcrumed on said housing withits Weight arms engaging said slidable means for moving saidslidable'means into and out of contracting engagement withv saidyresilient rmembers but adapted to permit rotation of sai-d slidablemeans with said chuck.

3. In a dental handpiece, in combination, a housing, a chuck rotatablymounted in vthe housing and adapted t'o receive aburr shank having ashoulder, the shank-receiving end of the chuck being divided intoaplurality of resilient members extending fromsaid end of said chuck in-Wardly beyond said shoulder when the shank is seated in the chuck,projections on the inner faces of said resilient members and means,operable bya bifurcated'bell-crank lever vfulcrumed on the housing,slidable over the ends of said resilient members adapted to contractsaid members and bringY `saidrproj ectionsl intor engagement with saidshoulder. if A 4. In a dental handpieca in combination, a housing, achuck rotatably mounted ini the housing and adapted to receive a burrshank having ashoulderfA the shank-receiving end of the chuckbeingdivldedinto a plurality of resilient memland a lever whose bers`extending from said end of said'chuck in# Wardly beyond said shoulderwhen the shank is seated in they chuck and means slidable overl the endsof said members adapted to contract said members and a lever whoseWeight arm engages said slidable means and which is fulcrumed on saidhousing and adapted to move said slidable means into and out ofcontracting engagement with said resilient members. f

, 5. In a dental handpiece, in combination, a` housing. a chuckrotatably mounted in the hous` 6. In a dental handpiece, in combination,av

housing, a chuck rotatably mounted in the housing and adapted to receivea burr shank, the shankereceiving end of Said chuck being divided into aplurality of resilient members and means 1 slidable over said membersand adapted to con. tract said members to resiliently grip said shankweight arm engages said slidable means and which is fulcrumed on saidhousing and adapted to move said slidable member longitudinally of thechuck but to permit rota. tion of vsaid slidable member with the chuck.

7. In'a dental handpiece, in combination,

I housing, Ya chuck rotatably mounted in the housing, means slidableover the shank-receiving end 4of said chuck, resilient nie'ansfoperableby said slidable means for gripping said shank when seated in the chuckand lever means fulcrumed on the housing'and Whose weight arm engagesand is adapted vto longitudinally reciprocate said slidable means. v

l8.In` a dental handpiece,l in combination, a housing, a chuck rotatablymounted in thel housing, means slidable over the Ishank-receiving endof` said chuck, resilient means operable byksaid Islidable means forgripping said shank when seated in the chuck and lever means fulcrumed von the housing and whose Weight arm has a peripherally slidableengagement with and is adapted to reciprocate said slidable meanslongitudinally While permitting rotation of said slidable means with thechuck. I

9. In a dental handpiece having a housing, a burr shank chuck rotatablymounted in the housing and clamping means moveable longitudinally of thechuck for clamping and unclamping the shank, a bifurcated bell-cranklever fulcrumed on the housing having Weight arms engaging the clampingmeans to move the said means longitudinally and permit the rotation ofAsaid means `With-the chuckwlien clamped thereon.

HAROLD H. BEARDSl'aEY.

